Support Min/Max Height/Width on IView

src/Compatibility/Core/src/Android/Renderers/PageContainer.cs

@@ -46,7 +46,11 @@ protected override void OnLayout(bool changed, int l, int t, int r, int b)
 					(l, t, r, b) = Context.ToPixels(ipc.ContainerArea);
 				}
 
-				pageViewGroup.Measure(r - l, b - t);
+				var mode = MeasureSpecMode.Exactly;
+				var widthSpec = mode.MakeMeasureSpec(r - l);
+				var heightSpec = mode.MakeMeasureSpec(b - t);
+
+				pageViewGroup.Measure(widthSpec, heightSpec);
 				pageViewGroup.Layout(l, t, r, b);
 			}
 		}

src/Compatibility/Core/src/Android/VisualElementTracker.cs

@@ -96,7 +96,7 @@ public void UpdateLayout()
 				formsViewGroup.MeasureAndLayout(MeasureSpecFactory.MakeMeasureSpec(width, MeasureSpecMode.Exactly), MeasureSpecFactory.MakeMeasureSpec(height, MeasureSpecMode.Exactly), x, y, x + width, y + height);
 				Performance.Stop(reference, "MeasureAndLayout");
 			}
-			else if (aview is LayoutViewGroup && width == 0 && height == 0)
+			else if ((aview is LayoutViewGroup || aview is PageViewGroup) && width == 0 && height == 0)
 			{
 				// Nothing to do here; just chill.
 			}

src/Controls/src/Core/HandlerImpl/ScrollView.Impl.cs

@@ -56,8 +56,11 @@ protected override Size MeasureOverride(double widthConstraint, double heightCon
 			// The value from ComputeDesiredSize won't account for any margins on the Content; we'll need to do that manually
 			// And we'll use ResolveConstraints to make sure we're sticking within and explicit Height/Width values or externally
 			// imposed constraints
-			var desiredWidth = ResolveConstraints(widthConstraint, Width, defaultSize.Width + contentMargin.HorizontalThickness);
-			var desiredHeight = ResolveConstraints(heightConstraint, Height, defaultSize.Height + contentMargin.VerticalThickness);
+			var width = (this as IView).Width;
+			var height = (this as IView).Height;
+
+			var desiredWidth = ResolveConstraints(widthConstraint, width, defaultSize.Width + contentMargin.HorizontalThickness);
+			var desiredHeight = ResolveConstraints(heightConstraint, height, defaultSize.Height + contentMargin.VerticalThickness);
 
 			DesiredSize = new Size(desiredWidth, desiredHeight);
 			return DesiredSize;

src/Controls/src/Core/HandlerImpl/VisualElement/VisualElement.Impl.cs

@@ -1,4 +1,5 @@
-using Microsoft.Maui.Graphics;
+using System;
+using Microsoft.Maui.Graphics;
 using Microsoft.Maui.Layouts;
 
 namespace Microsoft.Maui.Controls
@@ -118,8 +119,99 @@ Semantics IView.Semantics
 		internal Semantics SetupSemantics() =>
 			_semantics ??= new Semantics();
 
-		double IView.Width => WidthRequest;
-		double IView.Height => HeightRequest;
+		static void ValidatePositive(double value, string name) 
+		{
+			if (value < 0)
+			{
+				throw new InvalidOperationException($"{name} cannot be less than zero.");
+			}
+		}
+
+		double IView.Width
+		{
+			get
+			{
+				if (!IsSet(WidthRequestProperty))
+				{
+					return Primitives.Dimension.Unset;
+				}
+
+				// Access once up front to avoid multiple GetValue calls
+				var value = WidthRequest;
+				ValidatePositive(value, nameof(IView.Width));
+				return value;
+			}
+		}
+
+		double IView.Height
+		{
+			get
+			{
+				if (!IsSet(HeightRequestProperty))
+				{
+					return Primitives.Dimension.Unset;
+				}
+
+				// Access once up front to avoid multiple GetValue calls
+				var value = HeightRequest;
+				ValidatePositive(value, nameof(IView.Height));
+				return value;
+			}
+		}
+
+		double IView.MinimumWidth
+		{
+			get
+			{
+				if (!IsSet(MinimumWidthRequestProperty))
+				{
+					return Primitives.Dimension.Minimum;
+				}
+
+				// Access once up front to avoid multiple GetValue calls
+				var value = MinimumWidthRequest;
+				ValidatePositive(value, nameof(IView.MinimumWidth));
+				return value;
+			}
+		}
+
+		double IView.MinimumHeight
+		{
+			get
+			{
+				if (!IsSet(MinimumHeightRequestProperty))
+				{
+					return Primitives.Dimension.Minimum;
+				}
+
+				// Access once up front to avoid multiple GetValue calls
+				var value = MinimumHeightRequest;
+				ValidatePositive(value, nameof(IView.MinimumHeight));
+				return value;
+			}
+		}
+
+		double IView.MaximumWidth
+		{
+			get
+			{
+				// Access once up front to avoid multiple GetValue calls
+				var value = MaximumWidthRequest;
+				ValidatePositive(value, nameof(IView.MaximumWidth));
+				return value;
+			}
+		}
+
+		double IView.MaximumHeight
+		{
+			get
+			{
+				// Access once up front to avoid multiple GetValue calls
+				var value = MaximumHeightRequest;
+				ValidatePositive(value, nameof(IView.MaximumHeight));
+				return value;
+			}
+		}
 
 		Thickness IView.Margin => Thickness.Zero;
 	}

src/Controls/src/Core/VisualElement.cs

@@ -272,13 +272,17 @@ void InvalidateGradientBrushRequested(object sender, EventArgs e)
 		public static readonly BindableProperty TriggersProperty = TriggersPropertyKey.BindableProperty;
 
 
-		public static readonly BindableProperty WidthRequestProperty = BindableProperty.Create("WidthRequest", typeof(double), typeof(VisualElement), -1d, propertyChanged: OnRequestChanged);
+		public static readonly BindableProperty WidthRequestProperty = BindableProperty.Create(nameof(WidthRequest), typeof(double), typeof(VisualElement), -1d, propertyChanged: OnRequestChanged);
 
-		public static readonly BindableProperty HeightRequestProperty = BindableProperty.Create("HeightRequest", typeof(double), typeof(VisualElement), -1d, propertyChanged: OnRequestChanged);
+		public static readonly BindableProperty HeightRequestProperty = BindableProperty.Create(nameof(HeightRequest), typeof(double), typeof(VisualElement), -1d, propertyChanged: OnRequestChanged);
 
-		public static readonly BindableProperty MinimumWidthRequestProperty = BindableProperty.Create("MinimumWidthRequest", typeof(double), typeof(VisualElement), -1d, propertyChanged: OnRequestChanged);
+		public static readonly BindableProperty MinimumWidthRequestProperty = BindableProperty.Create(nameof(MinimumWidthRequest), typeof(double), typeof(VisualElement), -1d, propertyChanged: OnRequestChanged);
 
-		public static readonly BindableProperty MinimumHeightRequestProperty = BindableProperty.Create("MinimumHeightRequest", typeof(double), typeof(VisualElement), -1d, propertyChanged: OnRequestChanged);
+		public static readonly BindableProperty MinimumHeightRequestProperty = BindableProperty.Create(nameof(MinimumHeightRequest), typeof(double), typeof(VisualElement), -1d, propertyChanged: OnRequestChanged);
+
+		public static readonly BindableProperty MaximumWidthRequestProperty = BindableProperty.Create(nameof(MaximumWidthRequest), typeof(double), typeof(VisualElement), double.PositiveInfinity, propertyChanged: OnRequestChanged);
+
+		public static readonly BindableProperty MaximumHeightRequestProperty = BindableProperty.Create(nameof(MaximumHeightRequest), typeof(double), typeof(VisualElement), double.PositiveInfinity, propertyChanged: OnRequestChanged);
 
 		[EditorBrowsable(EditorBrowsableState.Never)]
 		public static readonly BindablePropertyKey IsFocusedPropertyKey = BindableProperty.CreateReadOnly("IsFocused",
@@ -436,6 +440,18 @@ public double MinimumWidthRequest
 			set { SetValue(MinimumWidthRequestProperty, value); }
 		}
 
+		public double MaximumHeightRequest
+		{
+			get { return (double)GetValue(MaximumHeightRequestProperty); }
+			set { SetValue(MaximumHeightRequestProperty, value); }
+		}
+
+		public double MaximumWidthRequest
+		{
+			get { return (double)GetValue(MaximumWidthRequestProperty); }
+			set { SetValue(MaximumWidthRequestProperty, value); }
+		}
+
 		public double Opacity
 		{
 			get { return (double)GetValue(OpacityProperty); }
@@ -1038,6 +1054,10 @@ static void OnRequestChanged(BindableObject bindable, object oldvalue, object ne
 			{
 				fe.Handler?.UpdateValue(nameof(IView.Width));
 				fe.Handler?.UpdateValue(nameof(IView.Height));
+				fe.Handler?.UpdateValue(nameof(IView.MinimumHeight));
+				fe.Handler?.UpdateValue(nameof(IView.MinimumWidth));
+				fe.Handler?.UpdateValue(nameof(IView.MaximumHeight));
+				fe.Handler?.UpdateValue(nameof(IView.MaximumWidth));
 			}
 
 			((VisualElement)bindable).InvalidateMeasureInternal(InvalidationTrigger.SizeRequestChanged);

src/Controls/tests/Core.UnitTests/Layouts/LayoutCompatTests.cs

@@ -41,7 +41,7 @@ public void GridInsideStackLayout()
 			var stackLayout = new StackLayout() { IsPlatformEnabled = true };
 			var grid = new Grid() { IsPlatformEnabled = true, HeightRequest = 50 };
 			var label = new Label() { IsPlatformEnabled = true };
-			var expectedSize = new Size(50, 50);
+			var expectedSize = new Size(100, 50);
 
 			var view = Substitute.For<IViewHandler>();
 			view.GetDesiredSize(default, default).ReturnsForAnyArgs(expectedSize);
@@ -51,7 +51,7 @@ public void GridInsideStackLayout()
 			grid.Children.Add(label);
 			contentPage.Content = stackLayout;
 
-			var rect = new Rectangle(0, 0, 50, 100);
+			var rect = new Rectangle(Point.Zero, expectedSize);
 			(contentPage as IView).Measure(expectedSize.Width, expectedSize.Height);
 			(contentPage as IView).Arrange(rect);
 

src/Core/src/Core/IView.cs

@@ -60,20 +60,40 @@ public interface IView : IElement, ITransform
 		Paint? Background { get; }
 
 		/// <summary>
-		/// Gets the bounds of the View.
+		/// Gets the bounds of the View within its container.
 		/// </summary>
 		Rectangle Frame { get; set; }
 
 		/// <summary>
-		/// Gets the specified width of this View. 
+		/// Gets the specified width of the IView. 
 		/// </summary>
 		double Width { get; }
 
 		/// <summary>
-		/// Gets the specified height of this View. 
+		/// Gets the specified minimum width constraint of the IView, between zero and double.PositiveInfinity.
+		/// </summary>
+		double MinimumWidth { get; }
+
+		/// <summary>
+		/// Gets the specified maximum width constraint of the IView, between zero and double.PositiveInfinity.
+		/// </summary>
+		double MaximumWidth { get; }
+
+		/// <summary>
+		/// Gets the specified height of the IView. 
 		/// </summary>
 		double Height { get; }
 
+		/// <summary>
+		/// Gets the specified minimum height constraint of the IView, between zero and double.PositiveInfinity.
+		/// </summary>
+		double MinimumHeight { get; }
+
+		/// <summary>
+		/// Gets the specified maximum height constraint of the IView, between zero and double.PositiveInfinity.
+		/// </summary>
+		double MaximumHeight { get; }
+
 		/// <summary>
 		/// The Margin represents the distance between an view and its adjacent views.
 		/// </summary>

src/Core/src/Handlers/View/ViewHandler.cs

@@ -22,6 +22,10 @@ public abstract partial class ViewHandler : ElementHandler, IViewHandler
 			[nameof(IView.FlowDirection)] = MapFlowDirection,
 			[nameof(IView.Width)] = MapWidth,
 			[nameof(IView.Height)] = MapHeight,
+			[nameof(IView.MinimumHeight)] = MapMinimumHeight,
+			[nameof(IView.MaximumHeight)] = MapMaximumHeight,
+			[nameof(IView.MinimumWidth)] = MapMinimumWidth,
+			[nameof(IView.MaximumWidth)] = MapMaximumWidth,
 			[nameof(IView.IsEnabled)] = MapIsEnabled,
 			[nameof(IView.Opacity)] = MapOpacity,
 			[nameof(IView.Semantics)] = MapSemantics,
@@ -138,6 +142,26 @@ public static void MapHeight(ViewHandler handler, IView view)
 			((NativeView?)handler.NativeView)?.UpdateHeight(view);
 		}
 
+		public static void MapMinimumHeight(ViewHandler handler, IView view)
+		{
+			((NativeView?)handler.NativeView)?.UpdateMinimumHeight(view);
+		}
+
+		public static void MapMaximumHeight(ViewHandler handler, IView view)
+		{
+			((NativeView?)handler.NativeView)?.UpdateMaximumHeight(view);
+		}
+
+		public static void MapMinimumWidth(ViewHandler handler, IView view)
+		{
+			((NativeView?)handler.NativeView)?.UpdateMinimumWidth(view);
+		}
+
+		public static void MapMaximumWidth(ViewHandler handler, IView view)
+		{
+			((NativeView?)handler.NativeView)?.UpdateMaximumWidth(view);
+		}
+
 		public static void MapIsEnabled(ViewHandler handler, IView view)
 		{
 			((NativeView?)handler.NativeView)?.UpdateIsEnabled(view);

src/Core/src/Handlers/View/ViewHandlerOfT.Android.cs

@@ -3,6 +3,7 @@
 using Android.Content;
 using Android.Views;
 using Microsoft.Maui.Graphics;
+using static Microsoft.Maui.Primitives.Dimension;
 
 namespace Microsoft.Maui.Handlers
 {
@@ -55,25 +56,30 @@ public override Size GetDesiredSize(double widthConstraint, double heightConstra
 			}
 
 			// Create a spec to handle the native measure
-			var widthSpec = CreateMeasureSpec(widthConstraint, VirtualView.Width);
-			var heightSpec = CreateMeasureSpec(heightConstraint, VirtualView.Height);
+			var widthSpec = CreateMeasureSpec(widthConstraint, VirtualView.Width, VirtualView.MaximumWidth);
+			var heightSpec = CreateMeasureSpec(heightConstraint, VirtualView.Height, VirtualView.MaximumHeight);
 
 			nativeView.Measure(widthSpec, heightSpec);
 
 			// Convert back to xplat sizes for the return value
 			return Context.FromPixels(nativeView.MeasuredWidth, nativeView.MeasuredHeight);
 		}
 
-		int CreateMeasureSpec(double constraint, double explicitSize)
+		int CreateMeasureSpec(double constraint, double explicitSize, double maximumSize)
 		{
 			var mode = MeasureSpecMode.AtMost;
 
-			if (explicitSize >= 0)
+			if (IsExplicitSet(explicitSize))
 			{
 				// We have a set value (i.e., a Width or Height)
 				mode = MeasureSpecMode.Exactly;
 				constraint = explicitSize;
 			}
+			else if (IsMaximumSet(maximumSize))
+			{
+				mode = MeasureSpecMode.AtMost;
+				constraint = maximumSize;
+			}
 			else if (double.IsInfinity(constraint))
 			{
 				// We've got infinite space; we'll leave the size up to the native control

src/Core/src/Handlers/View/ViewHandlerOfT.iOS.cs

@@ -1,5 +1,6 @@
 using Microsoft.Maui.Graphics;
 using UIKit;
+using static Microsoft.Maui.Primitives.Dimension;
 
 namespace Microsoft.Maui.Handlers
 {
@@ -46,11 +47,6 @@ public override Size GetDesiredSize(double widthConstraint, double heightConstra
 				return new Size(widthConstraint, heightConstraint);
 			}
 
-			var explicitWidth = VirtualView.Width;
-			var explicitHeight = VirtualView.Height;
-			var hasExplicitWidth = explicitWidth >= 0;
-			var hasExplicitHeight = explicitHeight >= 0;
-
 			var sizeThatFits = nativeView.SizeThatFits(new CoreGraphics.CGSize((float)widthConstraint, (float)heightConstraint));
 
 			var size = new Size(
@@ -63,8 +59,37 @@ public override Size GetDesiredSize(double widthConstraint, double heightConstra
 				size = new Size(nativeView.Frame.Width, nativeView.Frame.Height);
 			}
 
-			return new Size(hasExplicitWidth ? explicitWidth : size.Width,
-				hasExplicitHeight ? explicitHeight : size.Height);
+			var finalWidth = ResolveConstraints(size.Width, VirtualView.Width, VirtualView.MinimumWidth, VirtualView.MaximumWidth);
+			var finalHeight = ResolveConstraints(size.Height, VirtualView.Height, VirtualView.MinimumHeight, VirtualView.MaximumHeight);
+
+			return new Size(finalWidth, finalHeight);
+		}
+
+		double ResolveConstraints(double measured, double exact, double min, double max) 
+		{
+			var resolved = measured;
+
+			if (IsExplicitSet(exact))
+			{
+				// If an exact value has been specified, try to use that
+				resolved = exact;
+			}
+
+			if (resolved > max)
+			{
+				// Apply the max value constraint (if any)
+				// If the exact value is in conflict with the max value, the max value should win
+				resolved = max;
+			}
+
+			if (resolved < min)
+			{
+				// Apply the min value constraint (if any)
+				// If the exact or max value is in conflict with the min value, the min value should win
+				resolved = min;
+			}
+
+			return resolved;
 		}
 
 		protected override void SetupContainer()